The aim of this work was to evaluate the estomatal behavior and the leaf water potential in Mimosa caesalpiniifolia, Enterolobium contortisiliquum and Tabebuia aurea young plants cultivated under water stress. This work was performed in greenhouse of the Laboratório de Fisiologia Vegetal of the Universidade Federal Rural de Pernambuco, Brazil. Seedlings were submitted to two water treatment (100% and 50% pot capacity). On the 5th, 7th, 13th and 22th days of water treatments, the transpiration (E), diffusive resistance (Rs), leaf temperature (Tfol), air temperature (Tar), relative air humidity (UR), photossynthetically active radiation (PAR) and vapour pressure deficit (DPV) were evaluated at 7, 9, 12, 15h. After 30th days the leaf water potential (Yw) was measured, between 9-10h. The highest values of E were registered between 9-12h for all the species, although the stressed plants presented inferior values compared to the control plants. The opposite was verified for the Rs, however the differences in the magnitude and values among species and hours of evaluated were observed. The stomatal behavior of the stressed plants of E. contortisiliquum was influenced by the Tar and the M. caesalpiniifolia was influenced by the UR and PAR. The Yw decreased with the placing of stress, with reduction as much as 155%. The leaf temperature did not show a good indicator on the effects of water stress on the species studied.
water potential; diffusive resistance; transpiration
